Apparatuses and engines, burn various organic substances, exhaust gases containing NOx, CO, unburnt hydrocarbons, etc. Such exhaust gases have so far been converted basically by reactions to change carbon compounds into carbon dioxide and water and to change nitrogen oxides into nitrogen gas, using catalysts of platinum group elements carried by ceramics.
One of the present inventors filed an application for patent registration of amorphous alloy electrode materials containing Ni-Ta-Pt group metals as essential components, for generation of oxygen gas in the hydrolysis of aqueous solutions, under Japanese Patent Kokai No. 61-281889.
Furthermore, three of the present inventors filed applications for patent registration of surface activated amorphous alloys as electrodes for electrrolyzing solutions, comprising one or more elements of Ti, Zr, Nb and Ta, and Ni and platinum group metals, and also of an activation treatment process for them under Japanese Patent Kokai Nos. 62-96633, 62-96634 and 62-96636 and moreover filed an application for patent registration of similar surface activated supersaturated solid solution alloys for electrodes for electrolyzing solutions and also of an activation treatment process for them under Japanese Patent Kokai No. 62-96635.
In addition, the present inventors found surface activated amorphous alloys for methanol based fuel cells, and filed an application for patent registration under Japanese Patent Kokai No. 63-11647.
The conventional catalysts with platinum group elements carried by ceramics used for conversion of the exhaust gases from various apparatuses and engines burning various organic substaces are high in reaction temperature and difficult to recover expensive platinum group elements.
Therefore, the development of any catalysts which can act at low temperatures to convert low temperature exhaust gases in the beginning of combustion, are high in activity and can be easily regenerated has been awaited.